Incandescent lamp.



C. EHPIERGE.

INGANDESCENT LAMP. APPLICATION FILED NOV. 5, 1913.

Patented Mar. 9, 1915.

Inventor: CharlesE'. Pierce,

Witnesses firm -W CHARLES E. PIERCE, 0F CAMBRIDGE, MASSACHUSETTS.

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'This invention relates to improvements -in incandescent lamps, having for its object ithe'provisi0n of a lamp so constructed as to prevent or render commercially impracticable its renewal,or, in other words, the substitution or attempted substitution of a new filament for the old one when the latter is burned out or otherwise rendered useless or ineilicient.

The invention will be best understood by reference to the following description when taken in connection with the accompanying illustration of one specific embodiment thereof, while its scope will be more particularly pointed out in the appended claims.

In the drawings: Figure 1 is a side elevation of a lamp embodying one form of the invention, the walls of the bulb being partly broken away to show the filament support more distinctly; Fig. 2 is a. sectional detail showing the prolongation of the filament support as it is used for exhausting the lamp; and Fi 3 is a similar view showing another modi cation of the invention.

Referring to the embodiment of the invention shown in Figs. 1 and 2, the same. is shown applied to a lamp of ordinary construction but of a type em loying a tungsten or similar filament. he lamp there shown is provided with the usual glass bulb 1 cemented or otherwise secured in the usual fashion to and within the metal base 2 and having a common: form of glass stem 3 through which pass the leading-in wires 4, which latter are joined to the ends of the filament 5. As is usual in this class of lamps the filament is supported by two sets of arms 6 and 7 extending laterally from a centrally arran ed filament support 8 carried by and exten ing from the stem 3. The su sort 8 is used in the form of a glass rod We ed to the stem and extending toward but terminating short of the tip 9 of the lamp bulb.

Specification of Letters Patent.

' Patented Mar. 9, 1915.

Application filed Novena-ber 5', 1913'. Serial No. 799,391.

In renewing a lamp of this type, it is customary to make a small opening at the tip of the bulb, the opening being large enough to insert instruments whereby the old filament may be withdrawn and re laced by a new one. A small glass tube is t on welded to the bulb at the point where the opening has been made, the bulb exhausted, and the tip again sealedofi' as when first manufactured. It is impracticable, however, to make this opening larger than a certain minimum; otherwise the labor cost of patching over the large opening and welding on the tube would be greater than the cost of manufacturing a new bulb. In the illustrative embodiment of my invention this fact is taken advantage of by so constructing the bulb at or ad acent its tip that entrance to the interior of the bulb cannot be had through the tip.

Referring to iga 1 and 2, the filament support 8 has a s ort prolongation 10 beyond the arms 7 and telescopically secured on this Prolon ation is the tubular extension member 11. he latter extends to and is connected to the bulb 1 at the inside. of the tip 9 so that a perforation sufficient to renew the filament must either be'at one side .of the tip or of such size as to be impracticable.

. The extension 11 may be tubular in form and utilized to exhaust the bulb in place of the tubular stem which is customarily fastened to the lamp bulb prior to exhaus tion. To this end the bulb 1' (see Fig. 2) may have welded thereto the tubular exhaust stem 12 when the bulb is assembled .on the base 2. The tubular exhaust stem 12 is prolonged within the bulb to form the extension member 11 of such size and so positioned as to fit over the prolongation 10 on the filament sup ort 8. One or more lateral openings 13 eing rovided in the extension member 11, the ulb is then exhausted through the tube 12 by connecting the same to the exhaust pipe 14, carrying out the usual process of exhaustion after which the exhaust stem 12 is closed and sealed off to form the tip 9 in the usual way. The attachment of the extension member to the tip of the bulb as described gives. additional rigidity and strength to the filament support 8. i

In Fig. 3 a modified form of the invention is shown wherein entrance through the bulb tip is prevented by means of an obstruction member 15in the form of a plate carried by an extension 16 of the filament support 17. 1 r 1 While I have herein shown and described for purposes of illustration one specific embodiment of the invention, it is to be understood' that the same is not limited to the details f construction and relative arrangement of parts but that extensive deviations may. be made therefrom without departing from the spirit thereof.

Claims: a v

1. A non-renewable "incandescent lamp .havinga bulb provided with a tip projecting from the bulb, a base, a'centrally arranged filament support extending from the stem, laterally extendingqsupporting arms on said support, a filament carried thereby, and a prolongation of the filament support extending to and connected with the bulb:

to prevent entrance through :the tip for purposes of renewal, the termination of said prolongation having a cross mctional area. 1 at least as great as thatvof the projecting tip, thereby overlying the-entire tip, and

thus preventing 'renewalof the filament.

2. A non-renewable :incandescent lamp having a bulbprovided with a tip projecting from the bulb, a base, a stem, a centrally arranged filament "support extending from thestem, a filament,and a prolongation on said support preventing entrance to the bulb through the tip for purposes of renewal, the termination of said prolongation having across sectional area at least as great as that of the projecting tip, thereby overlying the entire tip, and thus preventing renewal of the filament.

3. A non-renewable incandescent lamp having a bulb, a base, a stem, a centrally arranged filament support extending from the stem, and a tubular rolongation secured to theend of the fi lament support, said, prolongation having lateral openings within the bulb whereby a projection of saidprolongation may be employed to exhaust the lamp prior to sealing off.

4. A non-renewable, incandescent lamp having a bulb, a base,'a stem, a centrally arranged filament support extending from the stem, and a tubular prolongation secured to the-end-of the filament support,3said prolongation having communication with the interior of'the bulb, whereby the projection of saidprolongation mayflbefiemployed to exhaust the lamp prior to sealing off.

In testimony whereof, I have signed my name tothis specification, in the two subscribing witnesses.

CHARLES E. PIERCE.

presence of Witnesses:

EVERETT S. EMERY, Y E. EDNA SPRY. 

